Latex ILDs compared to High Resilience PU foam firmness
| I'm pretty sure my mattress maker told me that the one inch 44 ILD talalay latex layer and the 45 HR high density PU foam 3/4" were very close in firmness. But wouldn't they still have a different sensation? Latex being more bouncy and firm PU being less so.<BR><BR>I think I've just about given up trying to make my latex layers (only 2 inches) work for me. I couldn't figure out why husband's side of the bed felt firmer than mine. I swear mine seems to compress throughout the night and yet when I open my mattress I don't see any sagging or compressions. That includes the coils. But my husband's side didn't seem to be quite that way. Well, I opened his up and found NO latex inside! I had forgotten that I took the two 44 ILD layers and one 45 ID PU foam. He, on the other hand, had three layers of PU foam. 55, 45 and 45. Coils, too. No wonder if was firmer!<BR><BR>So, I kept the 55 PU foam in both of our mattresses and sandwiched the 44 ILD between the 45 PU foam. The 55 is the base over the coils ending up with the highest layer the 45 PU foam. We shall see how it works tonight! If my back is still sore, I plan to order two more layers of HR PU foam in 45 and 55 and we can both forget the latex! I'll keep it around just in case. <BR><BR>I really am beginning to wonder if my back and latex make a good match. I'm doubting it. |
Re: Latex ILDs compared to High Resilience PU foam firmness
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Something I find interesting is that IFD's of Polyurethane foam take bigger jumps than latex. PU goes from , for example, 33 to 44 to 55 to 77. I have inquiries into several places, including the Polyurethane Foam Association and "the foam guy" from a local custom mattress maker, to see if I can gain some understanding of why PU foam might be "firmer" than latex for a given IFD. One problem with mixing latex and PU foam is that people tend to prefer latex OR polyurethane foam, including memory foam. There just isn't much information out there about mixing the different foams. I occasionally read a comment from someone saying not to mix the different foams, but without any particular explanation for why they think it's not a good idea. Can anyone shed any light on that? |
Re: Latex ILDs compared to High Resilience PU foam firmness
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haysdb wrote: Something I find interesting is that IFD's of Polyurethane foam take bigger jumps than latex. PU goes from , for example, 33 to 44 to 55 to 77.</p><p>I have inquiries into several places, including the Polyurethane Foam Association and "the foam guy" from a local custom mattress maker, to see if I can gain some understanding of why PU foam might be "firmer" than latex for a given IFD. One problem with mixing latex and PU foam is that people tend to prefer latex OR polyurethane foam, including memory foam. There just isn't much information out there about mixing the different foams. I occasionally read a comment from someone saying not to mix the different foams, but without any particular explanation for why they think it's not a good idea. Can anyone shed any light on that? Heck, I have all three in my mattress. PU, latex and some memory foam. Now we'll see how they work together to make my back feel good! I may just have to go to all cotton if I can't come up with a solution soon! |
Re: Latex ILDs compared to High Resilience PU foam firmness
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I submitted the following question to the Polyurethane Foam Association: Are the IFDs of flexible polyurethane and latex measured the same way? A foam supplier has told me that an HR foam with an IFD of 34 will be about equivalent in firmness to an IFD 44 talalay latex. He says it relates to density, but pfa.org documents are explicit that IFD is not related to density. http://www.pfa.org/jifsg/jifsgs1.html It can't be related to resilience or support factor because latex will typically be at least as good as a PU foam in these two areas. Their reply... [1] IFD is measured the same way for both products. Many latex foam rubber products have greater compression modulus than conventional foam and HR foam products. In common terms, that's Support Factor. Here's what it means: IFD at 25% is a measured resistance to compression force. You could specify an HR foam with a 45 lbs IFD at 25% compression and essentially it would be equal to a latex product with an IFD of 44 lbs at 25% deflection IN TERMS OF SURFACE FIRMNESS. If you were then to measure the IFD at 65% compression, theoretically, the latex sample would have a higher number (greater support). Bob Luedeka Executive Director In other words, the ILD 44 latex should be MORE supportive than the 44 HR since it will have the same 25% ILD, and therefore the same surface firmness, but a higher 65% ILD, and therefore a better compression modulus or "support factor," for superior deep down support. I have also asked this question of Dewey at FloBeds. He didn't know the answer but was going to talk to his foam guy whom he says has a good feel for the equivalencies of the two foams. I am going to "get to the bottom of this" if it's humanly possible. [1] The forum rules specify that we can't quote emails, but this is purely informational and not personal in nature. This would seem to be in keeping with the "spirit" of the rules, if not the letter. This message was modified Sep 28, 2007 by haysdb
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Re: Latex ILDs compared to High Resilience PU foam firmness
I received samples of three different ILDs of 3.0 lb HR foam today from FoamOnline.
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